Something else is amiss. Disk Utility certaintly works on mirrored RAID sets in Lion. So you are dealing with something else.
Now, the loss of the Recovery partition is expected and described here http://support.apple.com/kb/HT4649
Try using the diskutil command line tool to repair permissions. Do this by following these steps:
1: Open Terminal
2: Type the following command followed by hitting return:
diskutil repairPermissions /
3: This will run and complete showing all things that were corrected (or incapable of correcting).
Once complete, check the health of your RAID set using:
And it is my strong opinion that mirroring a boot volume (especially in a mini) is the best way to mitigate single points of failure. In most cases, the internal storage of a mini is too small for most deployments. But the OS, including Open Directory, passwords, etc, will be difficult to rebuild in the event of a disk failure. Having a mirrored boot is the best way to protect against a drive failure and ensure uptime of the device.
Of course, we still need to shut the machine off to swap a bad drive, but I digress......